Means for automatically injecting fuel into engines



Dec. 25, 1951 E. B. MARR MEANS FOR AUTOMATICALLY INJECTING FUEL INTO ENGINES Filed Jan. 5, 1948 ATTORNEY R. n 1 MM .!III. a m m 5 M. M 4 m V 2 H M 3 fill S /T 0/ w 7.! P 6 .& fiin, w 6 0 T.

Patented Dec. 25, 1951 MEANS FOR AUTOMATICALLY INJECTING FUEL INTD ENGINES Earl B. Marr, Santa Clara, Calif. I Application January 5, 1948, Serial No. 502

1 Claim.

This invention relates to automatic fuel injection means for internal combustion engines.

An object of my invention is to provide auxiliary means for automatically admitting fuel to an engine when additional fuel is needed for its operation.

Another object of my invention is to provide auxiliary fuel delivery means for internal combustion engines which automatically admits a mixture of air and fuel to the intake manifold when the suction pressure therein is decreased because of the failure of the usual carburetor means to deliver sufficient quantities of fuel to meet the load requirements.

Other objects and advantages of my invention will be pointed out hereinafter, or will be indicated, or will be obvious to one skilled in the art upon an understanding of the present disclosure. For the purpose of this application I have elected to show herein certain forms and details of auxiliary means for delivering fuel to an internal combustion engine representative of my invention; it is to be understood, however. that the embodiment of my invention herein shown and described is for the purpose of illustration only and that therefore it is not to be rearded as exhaustive of the variations of the invention.

In the accompanying drawings:

Fig. l is a side elevation of my improved auxiliary means for automatically delivering fuel to an engine, showing parts of the latter in section;

Fig. 2 is an enlarged sectional view of the means;

Fig. 3 is a sectional View taken on the line 3-3 of Fig. 2; and

Fig. 4 is a sectional view of a check valve used with my invention.

Referring to the drawings the numeral I shows a conventional engine having a fuel intake maulfold 2.

My invention is preferably connected to the fuel intake manifold, and it operates independently of the carburetor or other means ordinarily used to supply fuel to the combustion chambers of the engine.

The main operating unit of my invention includes an elongated tubular casing 3 comprising two sections which are joined end to end by threaded means. The outlet end of the tubular casing is connected by means of a threaded nipple 4 to the fuel intake manifold 2, and the pposite end of the said casing has an intake opening 5 for admitting air under atmospheric pressure to the casing during the operation of the device.

her 6 to the chamber 1 during the operation of the device. The casing 3 is provided as at I!) with an annular inwardly protruding shoulder which is positioned in the chamber I, the said shoulder forming a valve seat against which the enlarged end portion II Of a valve element I2 may become positioned to discontinue the flow of fuel through the casing, as will be later described. There is a slight clearance between the periphery of the valve element I2 and the inner surface of the tubular casing to permit fuel to flow through the said casing to the intake'manifold when the valve element is unseated with respect to the valve seat I 0. The valve element I2 is formed with a tapered end portion having a series circularly arranged radially disposed slots or grooves I3 having their inner closed ends arranged in converging relationship, the said slots forming fuel passages which provide atomizing means for thoroughly mixing'the air and fuel before it is discharged into the intake manifold 2. A helical spring I4 engaging at its opposite ends with the discharge end of the casing 3 and with the valve element I2 exerts a predetermined pressure against the latter in a direction whereby its enlarged end portion I I may be unseated from the valve seat I!) when the suction in the manifold has decreased to a certain extent, as when the engine fails to function properly because of a deficiency in the fuel normally supplied from the carburetor to the combustion chambers.

An externally threaded jet member I5 having a restricted outlet opening I6 extends well into the chamber 6 of the casing 3. A connecting union I! having a restricted opening I8 connects the jet member I5 with an elbow fitting I9 forming a part of a fuel-delivery line 20 leading to a source of fuel, such as a gasoline tank. Connected in the line 20 is a ball type check valve 2| which functions in the usual manner to allow fuel to I proceed upwardly through the line 20 but not downwardly in a reverse direction. The arrangement of the check valve in the line 20 at a point substantially spaced from discharge end of the jet I5, makes it possible for a substantial charge of liquid fuel to be maintained in the upper part of the supply line at all times, preparatory to the operation of the device when conditions in the engine require an increase in the fuel supply.

In the normal operation of the engine the suction in the fuel intake manifold 2 is ordinarily such that the atmospheric pressure against the valve element H is utilized to overcome the tension of the spring 14 and cause the valve element H to assume a position closing the opening through the casing 3. When such a condition prevails there is no fuel supplied to the intake manifold by the present auxiliary fuel delivery means. When the suction in the fuel intake manifold decreases to a certain extent as when the engine requires a greater amount of fuel for its operation than is then being supplied by the usual fuel delivery means, the spring 14 functions to unseat the valve element l2 and allow a mixture of fuel and air to pass through the casing to the manifold. It is to be noted that the pressure exerted against the valve element l2 by the spring i4 is sufficient to overcome the atmospheric pressure in the opposite direction upon the said valve element when the suction pressure in the intake manifold decreases to a predetermined extent. In'this regard the force of the spring l4 against the valve element I2 is not suflicient to overcome theforces exerted in the opposite direction upon the said valve element by the atmospheric and suction pressures when the engine is operating in the normal manner, but when the suction decreases to a predetermined extent the spring operates to automatically unseat the valv and thereby permit the mixture of air and fuel to be drawn through the easing into the fuel intake manifold.

In operation it is to be noted that the liquid fuel proceeding upwardly through the line 20 passes through the Venturi-like opening 18 into the jet member l5. It then passes through the restricted outlet opening I 6 in the jet member I4 into the stream of moving air then entering the casing through the air inlet opening 5. The fuel entering and mixing with the air stream proceeds through the opening 9' into the chamber 1 past the enlarged portion ll of the valve element l2, through the radial slots I3 in the latter and thence into the fuel intake manifold 2 from whence it is distributed in the usual manner to the combustion chambers of the engine. The vaporization of the fuel and the thorough mixing thereof with the air is assisted by means of the small openings I6 and 9 and the small channels provided by the radial slots 13. Thus when the fuel enters the intake manifold it is suitably vaporized 4 and prepared for immediate use in the combustion chambers without further mixing or treatment.

What I claim is: An auxiliary carburetor for use with an internal combustion engine comprising an elongated casing having two chambers connected end to end, one of the chambers being a mixing chamber and having an air inlet and a fuel inlet arranged at substantially right angles to each other and the other chamber being an atomizing chamber and having a fuel inlet at one end in communication with th mixing chamber and a fuel .outlet at its opposite end adapted to be connected to the intake manifold of an engine, the said casing having a valve seat arranged in the atomizing chamber, a valve member mounted in the atomizing chamber and arranged .for movement between a closed position seated against the valve seat and an open position spaced from said valve seat, the said valve member having a conical end portion formed with circularly arranged spaced radial slots, the said slots having converging closed inner ends, and a compression spring mounted in the atomizing chamber in op erative engagement with the valve member for urging the said valve member toward its open position, the said valve member being adapted to be actuated to open or closed positions in accordance with fluid-pressure differentials formed in the operation of the engine.

' EARL B. MARR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,576,109 Forman et a1 Mar. 9, 1926 1,758,897 Evans May 13, 1930 1,956,992 Mallory May 1, 1934 2,310,984 Mock et al. Feb. 16, 1943 2,327,592 Chisholm Aug. 24, 1943 2,460,528 Oswald Feb. 1, 1949 FOREIGN PATENTS Number Country Date 561,328 France Oct. 19, 1923 

